Mathematics: Post your doubts here!

[Chooi1993]

Anyone know how to do q10 (ii)(b) ?
http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_w10_qp_33.pdf
Please help me ! Thanks

 

[sea_princess]

can someone please solve question 8 : ii (b)
http://www.xtremepapers.com/papers/...S Level/Mathematics (9709)/9709_w10_qp_33.pdf

 

[Aqsa Mohd]

can some one plz help me oct/nov 2010 p1 .. question 1 plz ..

 

[Dug]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w11_qp_13.pdf
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w11_ms_13.pdf
question 9 part(iii) found out till x^2<=25/4 again stuck with the inequality thing how come the answer is -5/2<=x<=0

please help

x^2 =<25/4
From here we get two inequalities,
x=< 5/2 and x>=-5/2
However, now we have to consider the domain of f(x) i.e x =<0.
To find the domain of g(f(x)) when both functions are defined for unalike values of x,
We find the domains of f(x) and g(f(x)) and make an intersection between them. In this case, the domain for f(x) is already given in the question and the domain of g(f(x)) is what we just came up with.

I assume you know the number line method and so you just have to use it to get the required answer.

Correct me if im wrong plz :
fx has a domain of x>a
gx has a domain of x>b
therefore the domain of gfx will be x>a.

This answers your question too.
1 shot 2 kills

 

[Dug]

can some one plz help me oct/nov 2010 p1 .. question 1 plz ..

Which variant?

 

[Becky250892]

QUESTION : A geometric progression has a third term of 20 and a sum to infinity which is three times the first term. Find the first term. [4]

 

[farhan143]

I HAVE A DOUBT in the question :

2010 may june paper 12



i cant get the answer right!!!!

 

[Chooi1993]

Anyone know how to do q10 (ii)(b) ? p3
http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_w10_qp_33.pdf
Please help me ! Thanks

 

[Aqsa Mohd]

Which variant?

its p11..

 

[2pac]

can someone please solve question 8 : ii (b)
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w10_qp_33.pdf

Hey,I also can't solve these kind of questions.Posted a question which had 2 theeta instead of 0.5 and sadly haven't gotten no response but its understandable as p1 examination is near.If you do at all get the answer for your query,please forward to me as well.
Thanks

 

[wajji345]

I HAVE A DOUBT in the question :

2010 may june paper 12

View attachment 8545

i cant get the answer right!!!!

Its about integration and derivation... I suck at it . ;D

 

[ffaadyy]

can some one plz help me oct/nov 2010 p1 .. question 1 plz ..

(x + 1/x)^2

Open the square bracket.

x^2 + 2(x)(1/x) + (1/x)^2
x^2 + 2 + 1/(x^2)

Now integrate with respect to 'x'.

x^2 + 2 + x^-2)
(x^3)/3 + 2x - 1/x + c

Therefore, the answer is '(x^3)/3 + 2x - 1/x + c'.

 

[Muhammad Bin Anis]

someone please help
May june 2010 , qp 11 ,
Q5 (ii), how dow we calculate the max and minimum values???


PLease reply quickly

 

[ffaadyy]

I HAVE A DOUBT in the question :

2010 may june paper 12

View attachment 8545

i cant get the answer right!!!!

π ∫ (a/x)^2 = 24 π
π ∫ (a^2/x^2) = 24 π

Both the pi's get cancelled so we are left with:

∫ (a^2/x^2) = 24

Integrate with respect to 'x':

∫ (a^2)(x^-2) = 24
(a^2) ∫ (x^-2) = 24
(a^2) (-1/x) = 24

Plug in the upper limit (x=3) and the lower limit (x=1) in the integrated equation.

(a^2) (-1/x) = 24
(a^2) [(-1/3) - (-1)] = 24
(a^2) [(-1/3) + 1] = 24
[2(a^2)]/3 = 24
2(a^2) = 72
a^2 = 36
a = 6

Therefore, a=6.

 

[farhan143]

π ∫ (a/x)^2 = 24 π

Integrate with respect to 'x':

∫ (a^2)(x^-2) = 24
(a^2) ∫ (x^-2) = 24
(a^2) (-1/x) = 24


.

i didn't get this part right!?
neither did i understand it can u explain me this part...

THank YoU!!

 

[ffaadyy]

i didn't get this part right!?
neither did i understand it can u explain me this part...

THank YoU!!

This is the formula used to find the volume when a region is rotated about the x-axis:

Volume = π ∫ ( y )^2

The equation 'y = (a/x)' is already mentioned in the question, simply put it inside the formula and solve it.

π ∫ ( y )^2
π ∫ ( a/x )^2

 

[redapple20]

Nah the 1 in which v have to calculate angle btw two lines using gradients...

 

[farhan143]

This is the formula used to find the volume when a region is rotated about the x-axis:

Volume = π ∫ ( y )^2

The equation 'y = (a/x)' is already mentioned in the question, simply put it inside the formula and solve it.

π ∫ ( y )^2
π ∫ ( a/x )^2

i meant how you integrated it!!!

 

[Dug]

Nah the 1 in which v have to calculate angle btw two lines using gradients...

Oh that...Here is an example.
We have 2 lines with gradients m=2 and m=3 respectively.
To find the angle between them,
tan theta = 2
theta = 63.4

tan theta = 3
theta = 71.6

Angle between them = 71.6 - 63.4 = 8.2

 

[ffaadyy]

i meant how you integrated it!!!

(a/x)^2
(a^2)/(x^2)
(a^2) (x^-2)

Now integrate 'x'.

(a^2) (x^-2)
(a^2) [(x ^-1)/-1]
- (a^2)/x